Hey yall I could use some help diagnosing what's wrong with my bike. It's a 02 fatty with a 88 carbed. It suddenly lost power cruising down the road and decided it did want oil in it and puked through the air filter and out of the tank. She will idle and Rev slightly not fully. Did a compression test got 128 on the front and 130 on the rear. I'm lost with this one. Any help would greatly be appreciated.

 

You failed to mention how many miles on the motor and whether or not any modifications have been done?

Compression is bit low but if you did not hold the carb slide open that would explain the results. When checking compression on a CV carbed motor, I pull the carb from the boot so there are no restrictions to air flow. The CV carb slide is vacuum operated so simply holding the throttle open does not move the slide up and out of the way.

Sounds like the motor could be sumping, so checking for sumping would be something I would do next. Next moves would be determined by whether the motor is sumping or not. Recheck compression if the test was not done correctly, i.e, fully charged battery, know accurate guage, throttle wide open, carb slide open.

 

Apologies on that. It has 61k and just basic mods like exhaust an a 45 mm mikuni. Held the throttle full open on the test. Excuse my illiterate on harley don't usually touch them. What is sumping

 

Sumping is a condition wherein scavenging oil from the sump (lower part of the crankcase) causing oil to accumlate in the sump. The flywheel assembly then as to try and overcome the resistance from swimming in the accumlated oil. Have you every tried to run in waist high water? There are several things that cause sumping but basically it boils down to the inability of the scavenge side of the oil pump to pull oil from the crankcase.

To check for sumping, after the motor has been run a bit, carefully remove the "plug" from the right (brake) side of the crankcase. 4 to 6 ounces should drain out but if more, the motor is sumping. The next step will be to open up the cam chest and try to find out why.

There may be another reason for the oil puking. The bike is a softail and you wouldn't be the first to have overfilled the crankcase by checking the oil, getting a low reading and topping off, not realizing that if the bike has been sitting for a day, week or for a while, oil has drained from the oil tank into the crankcase and topping off has over filled. Many a softail owner has experienced that situation.

Another possibile cause could be head breathers not functioning as they should.

You are just going to have to roll up your sleeves, drag out some tools and start chasing down the possible sources of the sumping. I don't have an answer for why the motor will idle but not rev but I would be looking in the cam chest and examining the oil pump, cams, chain tensioners, etc.

 

Thanks for the help I believe it is sumping I opened the timing cover and over a quart came out on top of that the cam tensioners are down to metal. Would it be best to replace the pump or new orings.

 

It would be great if you could post some pictures.

Maybe on the pump; definitely the tensioners. Google CYCO tensioners; they have proven to last longer than OEM. The cam plate, with cams has to come out and the cams have to come out of the cam plate to replace the tensioners; best practice anyway. This will turn into a larger project because both inner and outer cam bearings should be replaced. Some will suggest upgrading to later hydraulic tensioner and roller chain, and if funds are available, why not but for a basically stock motor, the OEM oil pump, is up to the task. Special tools are required to R/R the inner bearings and the cams and outer bearings may need to be pressed out and back in. Maybe you can find a local independent to do the whole job or at least to the press work required for outer cam bearings and cams. There is a DIY "oven/freezer" work around for that.

A good inspection of the oil pump will tell if it should be replaced; I suspect it might be toast. Look for scoring of the pump and the back of the cam plate. Check the internals, the gerotors, of the oil pump for damage. Crank run out should also be checked while the cam chest is open

You should get your hands on the service manual for your bike if you plan to DIY this project. It is not as difficult as it may sound but if you are not comfortable taking it on. Look for a local independent with a reputation for good work. If you decide to DIY the project, there is lots of help on this forum from guys smarter than me.

Of course, all new o-rings and parts can be ordered from your local dealer of from an online discount dealer like Newcastle or Surdyke. You can Google Ronnies HD for illustrations to identify the parts and part numbers you will need.

That's all I got for now; let us know how you plan to proceed and you can get plenty of help here.

 

I belive the pump is the culprit due to all the cracks on it got the tensioner and pump on its way now I would have never guessed it was that. But I did find out it has seh 203 cams in it. I bought the bike years ago with only 30k on it. So that's a plus.

 

What's the gerotors and inside the pump look like? Are you sure they are cracks? Just looks like a rough casting.

 

Next step is take a reading on the crank pinion shaft for runout. "IF" that pump is cracked, maybe the crank let go and took it out.

 

Need more pictures; internal pump cavity where the gerotors ride, gerotors and back side of cam plate where the pump rides.